Question

The length and breadth of a rectangle are 42 4/7m and 10 1/2m. Find the area of the rectangle.

Answer 1

Answer:

Here, l=(5.7±0.1)cm,b=(3.4±0.2)cm

Area, A = l×b=5.7×3.4=19.38cm

2

=19.0cm

2

(rounding off to two significant figures)

∴

A

△A

=±(

l

△l

+

b

△b

)

= ±(

5.7

0.1

+

3.4

0.2

)=±(

5.7×3.4

0.34+1.14

)=±

19.38

1.48

⇒△A=±

19.38

1.48

×A=±

19.38

1.48

×19.38=±1.48

△A=±1.5 (rounding off to two significant figures);

Area = (19.0±1.5)cm

2

.

Answer 2

Answer:

Area of rectangle=length×breadth

 lets assume, 

length (L)=2m

breadth (B)=70cm=70/100=0.7m    (cm converted to m)

∴ Area of rectangle =L×B

                              =2×0.7

                              =1.4 m square